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  1.  
    This, perhaps, is more of a thought experiment than a practical question.

    Would it, in principle or even in theory, be possible to approach construction details in a systematic way from first principles? That is, not relying on prior knowledge, experience, rules of thumb and so on.

    In other words would it be possible to devise an exhaustive series of checks which could be applied to any detail to determine whether it will work? Even just taking one aspect - say for example, 'will it keep water out'?

    The way construction details are developed in practice is nearly always somewhat ad hoc. Perhaps starting from a traditional or well established standard detail, with modifications made, consultation with product suppliers, discussion with a few people with general construction experience, and so on. There's always scope for things to not get thought about.

    A structural engineer will justify their design in a systematic way. Perhaps not quite from first principles - but nearly.

    I've never seen architectural detailing developed in that kind of way though. Is it because there's simply too much going on, and too many things that no-one has a definitive answer on?

    I don't know if folk will think this is a strange question. But I've always wished there was a book called 'construction detailing from first principles'. So that when you just aren't sure if something works - you'd go through a checking process which, when complete, would ensure that nothing had been overlooked. I've a feeling such a book would not be possible to write though.
    •  
      CommentAuthorfostertom
    • CommentTimeMay 9th 2018 edited
     
    Gd idea - think of all the 'experienced' practitioners it wd put out of work, if anyone cd work it out for themselves with a gd bit of study!

    Would it be 'black box' like PHPP, where you put in your proposed design and it rates its performance,
    or wd it be instructional, setting out somewhat isolated first-principles, which you'd then have to combine economically and non-conflicting (come to think, that combining cd be what experienced designing is about)?
  2.  
    No, I don't think I'm thinking of something 'black box'. Or maybe it could be to some extent.

    I don't think it need put experienced practitioners out of work because I think you're right - a lot of what designing is about is weighing up priorities and 'combining' or integrating many potentially conflicting requirements including cultural and aesthetic ones which are not really quantifiable and would be outwith the scope of what I'm imagining.

    I think it would let you confidently say things like 'this eaves detail will keep the water out' for a certain level of exposure but with a predicted lifespan. There would still be decisions about whether it's worth paying more for something that will last 50 years vs 10 years. But these decisions, integrating lots of different variables, could at least be based on more objective, quantifiable variables than tends to be the case at the moment.
    • CommentAuthormike7
    • CommentTimeMay 9th 2018 edited
     
    Your question reminds me of a book by the surgeon and writer Atul Gawande called 'The Checklist Manifesto' , about the use of checklists in the medical world. This quote on the subject says it better than I would:-

    "New York Times’ Freakonomics Blog review
    If there is one topic that I have no natural affinity for, it is checklists. I don’t use checklists. I’m not interested in checklists.

    Yet, against all odds, I read Atul Gawande’s new book about checklists, The Checklist Manifesto in one sitting yesterday, which is an amazing tribute to the book that Gawande has crafted. Not only is the book loaded with fascinating stories, but it honestly changed the way I think about the world. It is the best book I’ve read in ages.

    The book’s main point is simple: no matter how expert you may be, well-designed check lists can improve outcomes (even for Gawande’s own surgical team). The best-known use of checklists is by airplane pilots. Among the many interesting stories in the book is how this dedication to checklists arose among pilots."

    A checklist isn't quite what you were suggesting but it might go some way towards it. Me no architect, but as an engineer there have been times when I would have done better to use one, e.g. 1. will it be too noisy? 2 will it be too heavy? 3. can it be maintained? 4. I like it - but will enough others? ......etc, etc. While it may not help with the assessment of the various factors, it could at least help ensure that none are overlooked.
  3.  
    Yes, I think the 'checklist' principle is entirely relevant to my question. I'm aware of the benefits checklists have brought to medical outcomes.

    Certainly a version of 'construction detailing from first principles' could be in the form of a checklist. It would be interesting to sit down and try and write it. Would it be thousands of items long or would it be easier to create something more manageable than we might assume?
    • CommentAuthorlineweight
    • CommentTimeMay 9th 2018 edited
     
    There's one way that design differs from what an airline pilot or doctor does though - it tends to be an iterative process. So a checklist would have to be devised with this in mind. Certain things wouldn't be ticked off once but at each iteration. There'd have to be a way of preventing that from becoming too unwieldy.
    • CommentAuthorSigaldry
    • CommentTimeMay 9th 2018
     
    For a good overview and various 'rules of thumb' from a thermal perspective try:

    http://www.zerocarbonhub.org/sites/default/files/resources/reports/ZCH-ThermalBridgingGuide-Screen_0.pdf

    Totally get you though, that document focuses on thermal, but there is a lot more to it and some approaches are good at some things, but not as good at others. detailing needs to consider: buildability, keeping water out, minimizing air leakage, thermal performance, interstitial condensation risks, surface condensation risk, fire performance, structural performance, sound performance etc. and there is a huge amount of variance depending on the constructions proposed and how they go together.

    It's all potentially very complex, but there are some general principles that can perhaps be winnowed out.

    e.g. Thermally, generally, you can reduce the level of heat lost through a junction by ensuring continuity of insulation layers, or by overlapping of insulation layers, by using lower conductivity materials or by separating higher conductivity materials from each other by using lower conductivity ones (thermal breaks).
    • CommentAuthorIan1961
    • CommentTimeMay 9th 2018
     
    Re Checklists:
    It's not construction detailing but at the macro level pretty much all architects in the UK work to a common "Plan of Work" published by the RIBA:
    https://www.architecture.com/knowledge-and-resources/resources-landing-page/riba-plan-of-work

    Construction detailing was taught to us at the school of architecture I went to but not all of them do that. Over the last 30 years there's been a tendency toward increased specialism in design and now fewer architects than ever feel comfortable preparing complex detailed construction drawings. On larger projects these days big chunks of detailed design work are subbed out to specialist contractors or consultants.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMay 9th 2018
     
    I think this is a good idea and possibly used more by the timber frame builders than the traditional brick and block people.

    My very first topic on here was was about open source housing, that really just relied on basic engineering. Got bogged down is ridiculous detail that was totally irrelevant pretty quick though.

    It is still an area I would like to explore more.

    My initial thoughts about making checklists for a house are to start with the plot i.e. ground type, access, services, local labour skills, etc.

    Then work up i.e. foundation type.

    And so forth.
    • CommentAuthorborpin
    • CommentTimeMay 9th 2018
     
    Posted By: lineweightThere's one way that design differs from what an airline pilot or doctor does though - it tends to be an iterative process.
    You will find that in these spheres, the checklists do (or have) change(d) iteratively. Incidents investigated by the AAIB for instance will often recommend (or demand) changes to checklists.
    • CommentAuthorgravelld
    • CommentTimeMay 9th 2018
     
    I think there's a certain pushback against systems and checklists. Not sure what it is - the desire for the human to impose their "creativity"? Yet they derive significant benefits for the end user - the most important stakeholder - and in most cases allow creativity within the bounds of the system anyway.

    The E Myth Revisited, while not exactly an academic tome, changed some of my thinking on this (I used to subscribe to the romantic notions of talent or ability being all you needed).
  4.  
    Posted By: borpin
    Posted By: lineweightThere's one way that design differs from what an airline pilot or doctor does though - it tends to be an iterative process.
    You will find that in these spheres, the checklists do (or have) change(d) iteratively. Incidents investigated by the AAIB for instance will often recommend (or demand) changes to checklists.


    I don't mean iterative changes to the checklist but to the design itself.

    When a plane takes off it does it once. You don't start with an outline taking off, refine it to a semi developed takeoff and eventually settle on a finalised takeoff (which the passengers then ask to be a takeoff from a different airport).
  5.  
    Posted By: gravelldI think there's a certain pushback against systems and checklists. Not sure what it is - the desire for the human to impose their "creativity"? Yet they derive significant benefits for the end user - the most important stakeholder - and in most cases allow creativity within the bounds of the system anyway.

    The E Myth Revisited, while not exactly an academic tome, changed some of my thinking on this (I used to subscribe to the romantic notions of talent or ability being all you needed).


    If checklists and systems allowed me to do the technical parts of my work more efficiently and reliably - it would free up time and head-space to do the more 'creative' parts. And would welcome that.

    (Although I don't really think that design work can be separated out neatly into one or the other of those...every decision involves a bit of both)
    •  
      CommentAuthorfostertom
    • CommentTimeMay 9th 2018 edited
     
    Posted By: gravelldE Myth Revisited
    I was recommended that - "changed my life" - I thought it was quite loathesome! Employees as automata (unless 'revisited' means total revision of the 'original').

    Posted By: lineweighta lot of what designing is about is weighing up priorities and 'combining' or integrating many potentially conflicting requirements including cultural and aesthetic ones which are not really quantifiable and would be outwith the scope of what I'm imagining
    Bringing it back away from checklists, which are only one tool towards to 'combining' economically and non-conflicting.

    I agree with "cultural and aesthetic ones which are not really quantifiable and would be outwith the scope of what I'm imagining" - I was def referring to technical 'combining'.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMay 9th 2018 edited
     
    Posted By: fostertomI was def referring to technical 'combining'.
    If you start from a good engineering base, it is relatively easy to get the looks right, even if, in some peoples eyes, it is cheating.
    Going the other way can be really hard, think what Gaudi designed and they are still building.
    • CommentAuthorgravelld
    • CommentTimeMay 9th 2018
     
    Posted By: fostertomI was recommended that - "changed my life" - I thought it was quite loathesome! Employees as automata (unless 'revisited' means total revision of the 'original').
    That wasn't my takeaway. I think it relates to service businesses more than product ones (see the spin offs - E Myth Architect etc ).
    •  
      CommentAuthordjh
    • CommentTimeMay 9th 2018
     
    Posted By: fostertomWould it be 'black box' like PHPP

    PHPP isn't black box. It's a spreadsheet and you can look at how it works. As to why it works like that, there's a bunch of published research & presentations that go some way to explaining it at least. Starting with the infamous PH details book.
    •  
      CommentAuthordjh
    • CommentTimeMay 9th 2018
     
    Posted By: lineweightWould it, in principle or even in theory, be possible to approach construction details in a systematic way from first principles? That is, not relying on prior knowledge, experience, rules of thumb and so on.

    In other words would it be possible to devise an exhaustive series of checks which could be applied to any detail to determine whether it will work? Even just taking one aspect - say for example, 'will it keep water out'?

    Seems unlikely to me. There is too much variation in materials, situations, goals etc. Not to mention in the gap between as-designed and as-built.

    There aren't many areas outside the hard sciences where the 'engineering' is complete and foolproof. Patients still die. Aircraft still crash. Buildings still burn. I'll bet that the breast screening scheduling software had the benefit of a raft of quality and project management standards applied to it but did they work?
    •  
      CommentAuthordjh
    • CommentTimeMay 9th 2018
     
    Posted By: lineweightWould it, in principle or even in theory, be possible to approach construction details in a systematic way from first principles? That is, not relying on prior knowledge, experience, rules of thumb and so on.

    In other words would it be possible to devise an exhaustive series of checks which could be applied to any detail to determine whether it will work? Even just taking one aspect - say for example, 'will it keep water out'?

    Trying to be a bit more constructive than my last post, why not turn it from a thought experiment into a practical question?

    Make it even simpler than (forall X, does X keep the water out). Is it possible to write what you want just for a flat area of roof, ignoring edges? By flat, I don't mean horizontal, I just mean not curved. Although I suppose the special case of a horizontal roof would be even simpler.

    To start with the outer materials, there are clay tiles, concrete tiles, slates, wood shingles, plastic tiles (possibly reinforced), metal tiles, strips and sheets, rubber and plastic sheets etc etc. They all have different minimum slopes they can be used at, which vary according to local wind strength. They all have different impact resistance, which depends on where you live (next to a golf course, under a flight path). They have different flammability, which affects where they can be used. There are different possible methods of fixing many of them, and different overlaps in different situations.

    It seems to me that it's always going to be a case of identifying the relevant characteristics of the site, including any planning conditions, choosing a shortlist of possible candidate covering materials, then checking the BBA (or ETA in general) for encouragement or elimination.

    First principles won't help you decide whether the slope is great enough for a particular tile, or how many nails to use, or how much overlap between rows.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMay 9th 2018
     
    Posted By: djhFirst principles won't help you decide whether the slope is great enough for a particular tile, or how many nails to use, or how much overlap between rows.
    I would have thought that is exactly what first principles can tell you.
    Then you add in the safety margins.
    For any given tile overlap, known wind velocities, rainfall patterns you can work out how 'far up the crack' water can be drive.
    Same for fixings, the mass of the tiles, its angles, the wind loadings, strength of nails etc should tell you what is needed.
    That is what first principles is all about.
    • CommentAuthorgoodevans
    • CommentTimeMay 10th 2018
     
    Posted By: SteamyTeaFor any given tile overlap, known wind velocities, rainfall patterns you can work out how 'far up the crack' water can be drive.
    And that calculation - from first principles is a nightmare or impossible - and so from the top covering of the dwelling you are already using rules of thumb, experience, and results from experiments.
    • CommentAuthormike7
    • CommentTimeMay 10th 2018
     
    I think you're on a sticky wicket here, ST. (Exactly how sticky it is hard to say, using just First Principles). I can only see it being arguable if you upgrade Murphy's Law of The Cussedness of Inert Objects to the status of a First Principle - and a few other such laws along with it - and have precise knowledge of how these laws will work in any given situation.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMay 10th 2018
     
    I never said it was easy (the easy way is to do test), just that it is possible and it is what mathematical modelling of the physical environment is all about.
    I could explain more but more interested in reading this:
      Ian Stewart.jpg
    • CommentAuthorlineweight
    • CommentTimeMay 10th 2018
     
    If I'm to imagine a practical version of what I describe in the OP, then my definition of "first principles" could be fairly loose. I don't think everything would start from the laws of physics. To take the example of wind-driven rain, perhaps it would be a set of more general rules. Check for gaps of a certain type and orientation. Some guidance on minimum or maximum dimensions. Methods of sealing. I know this starts to sound like ending up back at rules of thumb or standard construction textbook, but what would be different is that there would be a methodical checking of everything. It wouldn't rely on you thinking to check something in a certain chapter of your textbook. It would also be focussed on general rules and an explanation of their purpose instead of example details to copy and modify. The danger of modifying an example detail is that you unwittingly modify something that you don't realise is critical to its functioning properly.

    Also in a practical sense - there wouldn't really be a need to check established 'systems' like roof tiles. They are well understood. The critical points are where those systems join others. So wall to roof details and so on. This is where all the non 'standard' stuff happens because even if your roof tile system has excellent documentation with lots of example eaves detail it's likely that none of them will quite match exactly what you want to do.

    One thing that comes to mind is leadwork. There are lots of very well established standard details for common situations. But sometimes I'll be detailing something that's nearly but not quite like one of those standard situations. Or maybe some kind of hybrid of two of them. In these cases what's correct is no longer definitive and you're left trying to use your judgement based on your best understanding of why certain things are a certain way in the standard details. But a more "first principles" approach might be better. The leadwork needs to extend X mm up the wall or down the roof slope *because* Y unless Z applies. Etc.
    •  
      CommentAuthorfostertom
    • CommentTimeMay 10th 2018
     
    First principles could mean fundamental laws of physics - big faff, as discussed - or it could mean comprehensive empirical data at a fine-detail level.

    So, when considering e.g. risk of wind-blown water penetration, take numerous examples of gaps and overlaps, investigate which of their physical parameters (width of gap, roughness, surface tension etc) make the difference, and empirically derive a graph/curve/table of effect A as parameter B varies. That plot can then be used to assess novel kinds of gap or overlap which display that parameter.

    Then the problem of interplay of several such parameters. That's where the First principles concept may prove impractical - assemblies often show characteristics which can't be predicted by their parts, or only in retrospect.
  6.  
    I found this book recently and realised it was everything I wish I'd discovered as a student: a plain speaking, first principles approach to details.

    https://www.wiley.com/en-gb/Architectural+Detailing%3A+Function%2C+Constructibility%2C+Aesthetics%2C+3rd+Edition-p-9781118881996

    Worth reading some of the excerpt on that link.

    It's a little like the systems theory approach of Christopher Alexander in 'A Pattern Language', only applied to details. So that 'detail patterns' like 'Overhang and Drip' or 'Drain and Weep' can be applied to various different areas of the building.

    Sounds like it might be what the original post was after, albeit not quite in checklist format.
    •  
      CommentAuthordjh
    • CommentTimeMay 11th 2018
     
    Posted By: Doubting_ThomasI found this book recently and realised it was everything I wish I'd discovered as a student: a plain speaking, first principles approach to details.

    https://www.wiley.com/en-gb/Architectural+Detailing%3A+Function%2C+Constructibility%2C+Aesthetics%2C+3rd+Edition-p-9781118881996

    Worth reading some of the excerpt on that link.

    It's a little like the systems theory approach of Christopher Alexander in 'A Pattern Language', only applied to details. So that 'detail patterns' like 'Overhang and Drip' or 'Drain and Weep' can be applied to various different areas of the building.

    Sounds like it might be what the original post was after, albeit not quite in checklist format.

    Looks an interesting book, though both expensive and out of stock, so I won't be buying it. I don't see any excerpts though?

    I'm sure the idea of pattern languages will appeal to some on here :bigsmile:
    •  
      CommentAuthorSteamyTea
    • CommentTimeMay 11th 2018
     
    Is Paisley a pattern language, a colourful Scottish.
  7.  
    <blockquote><cite>Posted By: djh</cite>I don't see any excerpts though?</blockquote>

    There's a drop down below the cover photo that says 'read an excerpt'.

    Links to chapter 01 here:
    https://media.wiley.com/product_data/excerpt/90/11188819/1118881990-10.pdf

    Agree on the fact that it's expensive though...
    •  
      CommentAuthordjh
    • CommentTimeMay 12th 2018
     
    Ah, thanks for that extra link, Tom. Chapter 1 certainly looks like good stuff, and seems to me to be pretty close to what Colin is looking for. I see Amazon and various other shops claim to have it in stock at a reduced price, so I'd be very tempted to buy a copy.
   
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